MICRF405

290MHz – 980MHz ISM Band

ASK / FSK Transmitter

MicroLead Frame and MLF are registered trademarks of Amkor Technologies

RadioWire is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

April 2006

M9999-041906

(408) 955-1690

General Description

The MICRF405 is a 290MHz-980MHz RF transmitter

IC designed for unlicensed ISM band operations. It's

designed to work in the North American 315MHz

and 915MHz bands as well as the European

433MHz and 868MHz bands. The device is fully

FCC Part 15.247 and EN300-220-compliant.

The transmitter consists of a FSK/ASK modulator,

PLL frequency synthesizer and a power amplifier.

The frequency synthesizer consists of a voltage-

controlled oscillator (VCO), a crystal oscillator, dual

modulus

prescaler,

programmable

frequency

dividers and a phase-detector. The loop-filter can be

internal or external. The output power of the power

amplifier can be programmed to eight levels. A lock

detect circuit detects when the PLL is in lock.

In FSK mode, the user can select between three

different modulation types allowing a data rate up to

200kbps. When selecting FSK modulation applied

with dividers, the MICRF405 is switching between to

sets of register values (M0,N0,A0:"0" and M1,N1

and A1:"1"). The second modulation type is closed

loop VCO modulation using the internal modulator

that applies the modulated data to the VCO. The

third FSK modulation type is Open loop VCO

modulation.

In ASK modulation, the user can select between two

modulation types, with or without spreading. In both

modes the modulation depth is programmable.

RadioWire

®

Features

• FSK/ASK transmitter

• Frequency programmable

• ASK modulation depth programmable

• High efficiency power amplifier

• Programmable output power

• Power down function

• MCU reference clock

• Base band package engine

• TX buffer

• No external tuning circuitry

Applications

• Meter reading

• Automotive

• Smart Home

• Remote control systems

• Residential Automation

• Wireless security system